MACROPODIDE 161 
the blind, naked, helpless young creatures (which in the Great 
Kangaroo (Fig. 53) scarcely exceed an inch in length) are attached 
by their mouths to the nipples of the mother, and are fed by 
milk injected into their stomach by the contraction of the muscle 
covering the mammary gland. 
The Kangaroos are all vegetable feeders, browsing on grass and 
various kinds of herbage, the smaller species also eating roots. 
They are naturally timid, inoffensive creatures ; but the larger ones 
when hard pressed will turn and defend themselves, sometimes 
killing a dog by grasping it in their fore paws, and inflicting 
terrible wounds with the sharp claws of their powerful hind legs, 
sustaining themselves meanwhile upon the tail. A few aberrant 
forms are arboreal. The great majority are inhabitants of Australia 
and Tasmania, forming one of the most prominent and characteristic 
features of the fauna of these lands, and in the scenery of the 
country, as well as the economy of nature, performing the part of 
the deer and antelopes of other parts of the world, which are 
entirely wanting in Australia. Kangaroos were very important 
sources of food-supply to the natives, and are hunted by the colon- 
ists, both for sport and with a view to their destruction, on account 
of the damage they naturally do in consuming the grass, now 
required for feeding cattle and sheep. Notwithstanding this, they 
have in some districts increased in numbers, owing to the sup- 
pression of their former enemies, the aborigines and the Dingo or 
native dog. A few species are found in New Guinea and the 
adjacent islands, which belong, in the zoological sense, to the 
Australian region. 
Before noticing the various generic types of the IMucropodide, a 
few words are necessary in respect of the tooth-change, and we may 
here quote the observations of Mr. O. Thomas on this subject. 
“The full dentition of the members of this family consists, in the 
upper jaw, first of three incisors, then of a small canine (often, 
however, suppressed, as in Fig. 55), and then of six cheek-teeth, 
of which the second in the series is the only one which has a milk 
or deciduous predecessor, and is therefore the one to be regarded 
as the last premolar of the typical mammalian dentition, The 
special characteristics that render the development and succession of 
the teeth in the Macropodide, and especially in the genus Macropus, 
so puzzling to systematic zoologists, are: firstly, a general pro- 
gression forwards in the jaw of the whole tooth-row, comparable to 
that found elsewhere only in the Elephants and some Sirenians ; 
and, secondly, the fact that before the tooth-change the first tooth 
of the series (p 3) and the single milk-tooth (dm 4) placed next to 
it, both of which fall out at the change, are respectively so very 
similar in shape and size to the first and second teeth of the 
permanent series, viz. the permanent premolar (p 4) and the first 
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